Battling Rootknot Nematodes

[Goodloe]

Good info, GoDawgs!

In contrast, I have been sinfully lazy about my tode problem this offseason. I'm going with all resistant varieties for my in-ground tomatoes this year, and will be growing a few OP varieties in containers. I'll see how things shake out this year and look into some mitigation strategies if needed.

btw...I could have really done without the link from CLEMSON...

GoDawgs, thank you for this immensely helpful post including the links. I have lots of things to try now!

[GoDawgs]

Glad to share info! And I hope that if anyone here has any treatment or method that they think possibly works to suppress RKN, they'll share it!

I'm going to run two separate trials this spring using summer squash which, along with cukes, seems to be the plants most susceptible to RKN in this garden. Right now the broccoli will be going down the middle of the bed where there's garlic along each side. That combo was great two springs ago. I think the broccoli benefitted from the extra nitrogen given to the garlic. When the broccoli comes out I will plant summer squash there.

The bed right next to that one will have green peas in it so when they're pulled out late May I'll put in more squash, use a molasses drench on those plants and see what happens.

I guess you could say that growing the early hybrid sweet corn in another RKN bed will be a third trial. It will be planted exactly like the successful heirloom dent corn was which was in 2' wide circles with 8 seeds spaced equally around the circumference of each circle. And, thanks to good notes, it will receive the exact same fertilizer regimen the heirloom got.

Come to think about it, while I have summer squash going I will test the usage of diatomaceous earth around their stems for squash bug suppression (another something I read about). I'm also going to try burying the squash stems 4' from the planting spot to initiate another rooting zone in case vine borers hit the main stem. Lots to do!

I have crab meal and shrimp meal on hand to put in the planting holes, then I’ll follow up with a molasses drench once the weather warms up. I also have about eight 20 gal. containers of vermicompost to incorporate.
(This is for the rose border across the front of the house being planted in native soil.)
Please keep us all posted on progress and observations, Dawgs!

[GoDawgs]

First update: The molasses experiment is under way. I seeded four hills of Early Prolific Straightneck squash on Apr 10. Each of two hills were drenched pre-planting with half a gallon of molasses water (1TBS/gal). The other two received plain water. The seeds all popped on 4/19, 20.

Second update: When the first cauliflower was pulled today from a bed known to have nematodes, the roots were completely healthy and knot free. The theory behind planting these early in a known nematode bed was to see if plant maturity afforded some resistance to the effects of nematodes.

Four cauliflowers were transplanted out Feb 10. All but one succumbed to an unexpected freeze and more plants were immediately started on 2/20. This harvested cauliflower (1st round sole survivor) was getting pretty mature when soil temps permanently eased above 65 (nematode wake up call) on April 6. It will be interesting to see how the newer ones (5 weeks younger) will fare. Right now they're setting heads.

Thanks for the update!

[GoDawgs]

It's also pea pickin' time, every other day. The two beds are like night and day. I think the nematodes are working on this one:



The other one looks pretty good with just a few puny plants in it. Now, this bed is on the same side of the garden as the other but it does get a tad of shade in the hottest part of the afternoon. I don't know if that's making a difference or not:



I'll know when they get pulled up what the roots look like. Overall, we're probably not going to be getting as many peas as we want so I'm going to plan on planting more in the fall. Never done that before but there's always a first time.

Meanwhile, those four experimental summer squash planted in a known infested bed are doing well. One of the two molasses treated squash is still a baby as that hill had to be reseeded so I'll have two ages of plants to look at.

I’ve also observed that once the sun gets to peas ... and the temps go up a bit ... foliage starts to yellow and crisp almost right away.
You should be able to grow peas in the fall, no problem. I grow them all winter despite frosts.

[rick9748]

Good info. seems all say abt. same thing.I am planting 4 beds solid with French marigolds only thing I will plant in beds this Summer.Fall cover all with Mustard.
Trying 2 new products; Monterey, Nematode Control +s Actionvate. Will post results after tomato season.

[AlittleSalt]

GoDawgs, It's good seeing pictures of you getting some results.

In my garden, the RKN didn't seem to bother the peas, but it was a complete different story for okra, peppers, and tomatoes. (Okra had no chance at all.) I haven't posted on your thread here because my garden also has/had Fusarium Wilt race 3 too. That garden is no longer used. I have been reading all along though, and seeing some good results is promising.

[GoDawgs]

It will be interesting to see the pea roots. The theory behind planting the brassicas and peas in a known RKN area was that they are planted and mainly grow in cooler soil temps while the 'todes are still inactive. Then by the time the 'todes get active the plants will be mature enough to resist and finish out. This was one of those springs where we had some heat early and the soil temps got into the 'tode activity range early.

So far, the broccoli, broccolini, cauliflower, cabbage, kale and collards are doing fine so I'm keeping my fingers crossed. And I'm making sure that any garden tools used on the non-nematode side of the garden are sprayed with 10% bleach solution before
they touch the soil.

[b54red]

I had no nematode damage on my cucumbers last year but already they are affecting this years crop. I move them every year and about 2 out of 3 years I seem to luck out. Last year my okra had no nematodes which was a first for me. I did mulch them heavily and kept them watered which seems to help with both cucumbers and squash. The affect of nematodes on bell peppers is less dramatic usually but some years I seem to plant them in the worst possible spot for nematodes and then don't have very good production and the plants die much sooner. Grafting has saved my tomato growing and I have really had no problems with nematodes or fusarium wilt since going to grafting all my tomatoes.

I just rebuilt all my beds and had to add more to them since I used 10 inch boards to replace my 8 inch boards. I am adding a lot more peat to the beds hoping the better water retention it provides will help reduce the nematode problems.

Bill

Originally Posted by b54red

I had no nematode damage on my cucumbers last year but already they are affecting this years crop. I move them every year and about 2 out of 3 years I seem to luck out. Last year my okra had no nematodes which was a first for me. I did mulch them heavily and kept them watered which seems to help with both cucumbers and squash. The affect of nematodes on bell peppers is less dramatic usually but some years I seem to plant them in the worst possible spot for nematodes and then don't have very good production and the plants die much sooner. Grafting has saved my tomato growing and I have really had no problems with nematodes or fusarium wilt since going to grafting all my tomatoes.

I just rebuilt all my beds and had to add more to them since I used 10 inch boards to replace my 8 inch boards. I am adding a lot more peat to the beds hoping the better water retention it provides will help reduce the nematode problems.

Bill

That’s a lot of work on your raised beds. What do you mulch with?

[rick9748]

Clemson U. told me the active ingredient in this product is a natural repellent of root knot nematodes.Trying this year and will post results in October.
Product; Monterey Nematode Control.
Please post any experience you have had.

[GoDawgs]

I figured it was time to look back on stuff I’ve been trying in the ‘Tode War fight since I began this thread. So here’s the latest update.

Using nematode beds in cold weather
In post #56 above I had a revelation about planting only cold weather crops in ‘toded beds because ‘todes are inactive in cold soil temps (below 64 degrees). Also planting in them other crops that ‘todes don’t like or don’t bother like alliums and corn. First, after spring ’18 all plants were removed from those six beds. In June ’18, the six infected beds were left fallow from then through mid Feb of this year with the exception of onions and scallions growing along the sides of one bed and garlic along the sides of another. Starve the little buggers!

In mid February I planted broccoli down the middle of the garlic bed, cabbage and broccolini in the 2nd, peas in two beds (one of those not a ‘toded bed), cauliflower and kale in the 4th and collards at the end of the 5th bed. In late April I planted an early corn in the 6th. Some literature says corn is affected and others say not as it’s a grass and nematodes don’t mess with it. Although I failed to note down the soil temps at planting time, they were at least in the 50’s for all but the corn which went in at 62 degrees.

As it turned out, nothing in those six beds except the one pea planting that was in a ‘tode bed had any indication of nematode damage. Those peas May 10th:



Even the collards and kale that stayed on into hot weather survived unscathed. Certainly soil temps got into the active range. I’m just wondering if that’s because by then the plants had gotten to their mature size and were big and tough enough to laugh at the ‘todes. But the roots were all clean except for that one bed of peas, a veg which has comparatively wimpy roots to begin with.

The Molasses Experiment
In post #60 above I listed some research I had found indicating that molasses, in addition to aiding nutrition uptake, can possibly deter nematodes. On April 10th I planted four hills of straightneck squash in nematode bed #5 where collards were planted on one end earlier. Soil temp was 62, minimal for squash germination and yet not quite warm enough to trigger nematode activity. Pre-plant, the soil of two of the hills received 1/2 gallon each of pre-plant molasses drench (1 TBS blackstrap molasses/gal and two did not. Unfortunately one of the molasses hills failed to germinate and was resown on April 25 so for a good while it lagged the others.

May 17th, 4 collards far end, two untreated hills, two molasses treated hills near end:



All hills were subsequently fertilized every two weeks with 4 cups of Miracle Grow solution and the two molasses hills also received two cups each of the pre-plant molasses solution. The larger treated hill was the first to set a squash, seemed to grow faster than the others and make more squash. Those hills are still out there, still look decent considering their age, managed to avoid the squash vine borers and are still producing. I’m amazed at that. Does molasses help nutrition uptake? I think so and I will play with that some more. Does molasses deter nematodes? I don’t know as in the end, the untreated squash did equally as well as the treated ones. However once they decline and I pull the plants, the roots will tell the story.

The “Resistance” Test
After the one bed of ‘toded green peas were pulled, I sowed that bed with Knucklehull field peas. This variety was specifically bought for planting due to supposed nematode resistance. So far, so good. Knucklehulls on 6/25, 21 days after sowing:



Marigolds
I am now only growing marigolds for the butterflies and the myriad of other pollinators who really love them. Research I’ve read indicate that to do any good they must be planted thickly, like a whole bed covered with plants planted 7” apart in all directions and then tilled in at a certain age. The ones I’ve tilled in before kept getting caught in the tines and it was a pain in the patoot. Not to mention how many plants I’d have to grow for just one 4x18’ bed or all the seed that would have to be bought. Impractical.

Alfalfa meal
In post #38 above, Gardenboy recommended the use of alfalfa pellets as a fertilizer and for the nematicidal properties of alfalfa component triacontanol. It slipped my mind but after rereading this thread and being reminded, I’ve done some internet searching on this and although I’ve not found any university studies I have found several growing/gardening links that concur, one being https://growingorganic.com/soil-guide/alfalfa-meal/. I need to stop by the feed & seed tomorrow and see what they have, hopefully something smaller than a 50 lb bag!

Soil Build-up
This continues gradually with regular replenishment of leaf mulch. I’m not tilling beds any more, trying to keep soil structure intact. It’s also too hard to clean and sanitize the tiller to prevent spread of nematodes from one bed to another. I do loosen the soil with the broadfork pre-planting. There’s also amendment of each planting hole and some rows with compost every time something new is planted. Purchase and incorporation of mass quantities of various amendments will not be happening at this time.

More Research

“Most nematode species are active during warm summer months and can’t penetrate roots at soil temperatures below 64°F. Therefore, you can reduce nematode injury to fall-planted crops such as carrots, lettuce, spinach, and peas by waiting until soil temperatures have dropped below 64°F. Plant summer vegetables as early as possible in spring before nematodes become active. Plants with larger root systems, even though nematode-infested, might be able to remain productive longer.”


Another chart of what are susceptible to nematodes, from:
http://extension.missouri.edu/nodawa...0Autosaved.pdf




Unfortunately, a new battleground emerges in a new bed, one side of a bush bean bed. The Golden Rods weren't looking good:



And the reason:



Fortunately so far it's just one side of the bed. Go figure.